Abstract:

An exposure apparatus projects a pattern of an original plate onto a
substrate through a projection optical system to expose the substrate to
the pattern. The exposure apparatus includes a supporting member
configured to support an optical element of the projection optical system
along the direction of gravitational force, and position adjustment
mechanisms disposed at least two different positions on the supporting
member and configured to press the optical element to displace the
optical element relative to the supporting member. The pressing force of
the position adjustment mechanisms against the optical element is changed
to move contact positions between the position adjustment mechanisms and
the optical element to displace the optical element relative to the
supporting member. Thus, optical performance adjustment of the optical
element is performed, and then all the position adjustment mechanisms are
made in non-contact state with the optical element.

Claims:

1. An apparatus comprising:a supporting member configured to support an
optical element of a projection optical system along a direction of
gravitational force; andposition adjustment mechanisms disposed at a
plurality of positions on the supporting member and configured to press
the optical element, with a pressing force, to displace the optical
element relative to the supporting member,wherein after the pressing
force is changed to move contact positions between the position
adjustment mechanisms and the optical element and optical performance
measurement of the optical element is performed, all the position
adjustment mechanisms are made in a non-contact state with the optical
element.

2. The exposure apparatus according to claim 1, wherein the position
adjustment mechanisms press the optical element toward a central axis.

3. The exposure apparatus according to claim 1, further comprising
position detection units configured to detect an amount of movement of
the optical element.

4. The exposure apparatus according to claim 1, wherein the position
adjustment mechanisms are thermal actuators controlled by a temperature
control unit, and the thermal actuators move the contact positions
between the thermal actuators and the optical element by a volume change
in the thermal actuators caused by a temperature change.

5. The exposure apparatus according to claim 1, wherein each of the
position adjustment mechanisms includes an actuator and a link mechanism
for changing magnification and direction of displacement of the actuator,
andwherein the link mechanism is brought into contact with the optical
element.

6. The exposure apparatus according to claim 3, wherein the position
detection units measure aberration of the projection optical system,
calculate an amount of movement of the optical element necessary to
settle the aberration within a tolerance, and displace the optical
element relative to the supporting member.

7. The exposure apparatus according to claim 3, wherein the position
detection units include a plurality of displacement sensors capable of
measuring at least two axes, andwherein, referring to values of
displacement sensors, the optical element is displaced relative to the
supporting member based on the amount of movement of the optical element
necessary to settle the aberration within a tolerance, which is
calculated from a result of aberration measurement by the projection
optical system.

8. The exposure apparatus according to claim 7, wherein the displacement
sensors are provided with an origin used as a reference for measuring an
absolute position of an object to be measured, and, when the position of
the optical element is displaced, the optical element is returned to the
position before displacing the optical element with reference to the
origin.

9. The exposure apparatus according to claim 1, further comprising:contact
detection units disposed at contact portions between the position
adjustment mechanisms and the optical element and configured to detect
contact therebetween,wherein, after the contact detection units detect
contact, an input given to the position adjustment mechanisms as a
command value determines an amount of movement of the optical element.

10. The apparatus according to claim 1 further comprisingposition
detection units configured to detect an amount of movement of the optical
element,wherein the position adjustment mechanisms are provided with two
different contact positions with the optical element to displace the
optical element in both positive and negative directions.

11. The exposure apparatus according to claim 1 further
comprising:position detection units each configured to detect an amount
of movement of the optical element; andcoupling members each configured
to connect the position adjustment mechanisms with the optical
element,wherein after contact positions between the position adjustment
mechanisms and the optical element are moved in one and opposite
directions to respectively press and pull the optical element, the
coupling members are bent.

12. A method for manufacturing a device by exposing a substrate using an
apparatus including;a projection optical system configured to project a
pattern of an original plate onto a substrate to expose the substrate to
the pattern,a supporting member configured to support an optical element
of the projection optical system along a direction of gravitational
force, andposition adjustment mechanisms disposed at a plurality of
positions on the supporting member and configured to press the optical
element, with a pressing force, to displace the optical element relative
to the supporting member,the method comprising:changing the pressing
force to move contact positions between the position adjustment
mechanisms and the optical element;performing optical performance
measurement of the optical element;making all the position adjustment
mechanisms in non-contact state with the optical element; anddeveloping
the exposed substrate.

13. A method for manufacturing a device by exposing a substrate by using
an exposure apparatus including;a projection optical system configured to
project a pattern of an original plate onto a substrate to expose the
substrate to the pattern,a supporting member configured to support an
optical element of the projection optical system along a direction of
gravitational force,position adjustment mechanisms disposed at a
plurality of positions on the supporting member and configured to press
the optical element to displace the optical element relative to the
supporting member, andposition detection units configured to detect an
amount of movement of the optical element,wherein the position adjustment
mechanisms are provided with two different contact positions with the
optical element to displace the optical element in positive and negative
directions, andthe method comprising:moving contact positions between the
position adjustment mechanisms and the optical element to displace the
optical element relative to the supporting member;performing optical
performance measurement of the optical element;making all the position
adjustment mechanisms in non-contact state with the optical element;
anddeveloping the exposed substrate.

14. The method according to claim 13, wherein the apparatus further
including coupling members configured to connect the position adjustment
mechanisms with the optical element, andwherein the moving contact
positions between the position adjustment mechanisms and the optical
element is in one and opposite directions to respectively press and pull
the optical element to displace the optical element relative to the
supporting member.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates to an exposure apparatus, which
projects a pattern of an original plate through a projection optical
system to expose a substrate to the pattern.

[0003]2. Description of the Related Art

[0004]In manufacturing a semiconductor device formed with an ultra-minute
pattern, a semiconductor exposure apparatus reduces and projects an image
of a circuit pattern of an original plate (a reticle) onto a substrate (a
wafer) to print the circuit pattern thereon. Improvement in resolution of
exposure apparatuses has been achieved to meet demands for forming finer
minute patterns to further increase the integration of semiconductor
devices.

[0005]To improve the resolution of an exposure apparatus, it is necessary
to improve the performance of a projection optical system for reducing
and projecting an image of a pattern of the original plate onto the
substrate. To improve the performance of the projection optical system,
it is necessary to improve the positional accuracy of each optical
element in a lens barrel, which includes a plurality of optical elements.

[0006]Japanese Patent Application Laid-Open No. 2001-124968 discusses a
method for assembling a projection optical system employing a cell
structure to position each optical element with high precision in
assembling process to reduce measured aberration within tolerance. After
assembling the projection optical system, it becomes necessary to correct
variation in optical performance caused by external factors such as shock
to the lens barrel or temperature change during transportation or
operation, thus position adjustment of optical elements is required.

[0007]Each of Japanese Patent Application Laid-Open No. 2001-343575,
Japanese Patent Application Laid-Open No. 2002-131605, and Japanese
Patent Application Laid-Open No. 2005-175271 discusses a method for
connecting actuators to an optical element through
displacement-transmitting members so that the optical element is
displaced by displacement of the actuators to perform position adjustment
of the optical element after assembling process.

[0008]With each optical element constituting a high-precision optical
system, it is also necessary to reduce degradation in optical performance
caused by deformation of each element due to external force or
birefringent as much as possible. Japanese Patent Publication No. 4-69885
discusses a method for fixing an optical element to a supporting member
by filling a space between the optical element and the supporting member
with an adhesive.

[0009]Adhesive-based fixing methods can reduce external force applied to
an optical element to greater extent than that of mechanical fixing
methods, and thus reduce deformation generated when assembling the
optical element. Further, this method for fixing an optical element by
filling a space between the optical element and the supporting member
with an adhesive is simpler and more space-saving than mechanical fixing
methods. Therefore, the method can be used without imposing severe space
restrictions when considering arrangement of an optical element in
optical design.

[0010]However, with the method for fixing an optical element by filling a
space between the optical element and the supporting member with an
adhesive, the adhesive changes its hardness and volume as it hardens.
Accordingly, external force is applied to the optical element to cause a
positional deviation, deformation, or birefringent of the optical
element.

[0011]With an exposure apparatus employing short-wavelength laser as a
light source, when the adhesive is irradiated with dispersion light, gas
is emitted therefrom. The emitted gas may contaminate the surface of the
optical element, which may cause degradation in transmissivity and
optical characteristics. Further, when the adhesive is irradiated with
dispersion light in the projection optical system, characteristics of the
adhesive may change and cause a positional deviation of the optical
element.

[0012]When the actuators are directly connected to the optical element,
external force applied to the optical element may change as the optical
element is driven by displacement of the actuators. Accordingly, a change
in optical characteristics due to the drive may arise.

[0013]In each of Japanese Patent Application Laid-Open No. 2001-343575,
Japanese Patent Application Laid-Open No. 2002-131605, and Japanese
Patent Application Laid-Open No. 2005-175271, since the actuators are
connected to the optical element through displacement-transmitting
members, the force by displacement of the actuators is not directly
applied to the optical element but is reduced by the
displacement-transmitting members. However, the lens barrel increases in
size because of the displacement-transmitting members included therein,
and the optical element is subjected to external force since it is fixed
to the supporting member.

SUMMARY OF THE INVENTION

[0014]The present invention is directed to an exposure apparatus, which
reduces influence of external force on an optical element to stabilize
optical performance.

[0015]According to an aspect of the present invention, an exposure
apparatus for projecting a pattern of an original plate to expose a
substrate thereto through a projection optical system includes a
supporting member configured to support an optical element of the
projection optical system along the direction of gravitational force, and
position adjustment mechanisms disposed at a plurality of positions on
the supporting member and configured to press the optical element to
displace the optical element relative to the supporting member, wherein
after the pressing force of the position adjustment mechanisms against
the optical element is changed to move contact positions between the
position adjustment mechanisms and the optical element to displace the
optical element relative to the supporting member and optical performance
measurement of the optical element is performed, all the position
adjustment mechanisms are made in non-contact state with the optical
element.

[0016]According to another aspect of the present invention, an exposure
apparatus for projecting a pattern of an original plate to expose a
substrate thereto through a projection optical system includes a
supporting member configured to support an optical element of the
projection optical system along the direction along the gravitational
force, position adjustment mechanisms disposed at a plurality of
positions on the supporting member and configured to press the optical
element to displace the optical element relative to the supporting
member, and position detection units configured to detect an amount of
movement of the optical element, wherein the position adjustment
mechanisms are provided with two different contact positions with the
optical element to displace the optical element in both positive and
negative directions, and wherein the contact positions between the
position adjustment mechanisms and the optical element are moved to press
the optical element to displace the optical element relative to the
supporting member, thus performing optical performance adjustment of the
optical element, and then all the position adjustment mechanisms are
brought into non-contact state with the optical element.

[0017]According to yet another aspect of the present invention, an
exposure apparatus for projecting a pattern of an original plate to
expose a substrate thereto through a projection optical system includes a
supporting member configured to support an optical element of the
projection optical system along the direction of gravitational force,
position adjustment mechanisms disposed at a plurality of positions on
the supporting member and configured to press the optical element to
displace the optical element relative to the supporting member, position
detection units each configured to detect an amount of movement of the
optical element; and coupling members each configured to connect the
position adjustment mechanisms with the optical element, wherein after
contact positions between the position adjustment mechanisms and the
optical element are moved in one and opposite directions to respectively
press and pull the optical element to displace the optical element
relative to the supporting member, and thus optical performance
adjustment of the optical element is performed, all the position
adjustment mechanisms are brought into non-contact state with the optical
element, and the coupling members are bent.

[0018]Further features and aspects of the present invention will become
apparent from the following detailed description of exemplary embodiments
with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]The accompanying drawings, which are incorporated in and constitute
a part of the specification, illustrate exemplary embodiments, features,
and aspects of the invention and, together with the description, serve to
explain the principles of the invention.

[0020]FIG. 1 is a partial configuration diagram of an exposure apparatus
according to a first exemplary embodiment of the present invention.

[0021]FIG. 2 is a partial configuration diagram of an exposure apparatus
according to a second exemplary embodiment of the present invention.

[0022]FIG. 3 is a partial configuration diagram of an exposure apparatus
according to a third exemplary embodiment of the present invention.

[0023]FIG. 4 is a partial configuration diagram of an exposure apparatus
according to a fourth exemplary embodiment of the present invention.

[0024]FIG. 5 is a partial configuration diagram of an exposure apparatus
according to a fifth exemplary embodiment of the present invention.

[0025]FIG. 6 is a partial configuration diagram of the exposure apparatus
according to the fifth exemplary embodiment of the present invention.

[0026]FIG. 7 is a partial configuration diagram of an exposure apparatus
according to a sixth exemplary embodiment of the present invention.

[0027]FIG. 8 is an overall configuration diagram of an exposure apparatus
according to an exemplary embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

[0028]Various exemplary embodiments, features, and aspects of the
invention will be described in detail below with reference to the
drawings.

[0029]FIG. 8 is an overall configuration diagram of an exposure apparatus
according to a first exemplary embodiment of the present invention. An
exposure apparatus 8 according to the first exemplary embodiment includes
a reticle 82a (an original plate), a wafer 84a (a substrate), a
projection optical system 83, an irradiation optical system 81, a reticle
stage 82, a wafer stage 84, an aberration measurement unit 85, an optical
element position adjustment device 86, and a position adjustment control
unit 87. The exposure apparatus 8 projects a pattern of the reticle 82a
onto the wafer 84a through the projection optical system 83 to expose the
wafer 84a to the pattern. The projection optical system 83 includes the
optical element position adjustment device 86 configured to adjust the
position of an optical element based on a command value sent by the
position adjustment control unit 87.

[0030]The irradiation optical system 81 includes an illumination light
source to illuminate the reticle 82a. The reticle stage 82 holds and
moves the reticle 82a. The wafer stage 84 holds and moves the wafer 84a.
The aberration measurement unit 85 includes an interferometer and a
wave-front aberration calculation unit to measure aberration of the
projection optical system 83.

[0031]FIG. 1 is a partial configuration diagram of the exposure apparatus
according to the first exemplary embodiment of the present invention. The
projection optical system 83 includes a supporting member 2, which
supports an optical element 1 in the direction of gravitational force.
The optical element 1 is a lens or a mirror. The direction of
gravitational force in FIG. 1 is negative direction of the Z axis. A
force generated by its own weight is exerted to the optical element 1.

[0032]Position adjustment mechanisms 3 are disposed at a plurality of
positions on the supporting member 2 to press the optical element 1 to
displace the optical element 1 relative to the supporting member 2. As
the position adjustment mechanisms 3 press the optical element 1 toward
its central axis, the optical element 1 is displaced in moving directions
of the contact positions with the position adjustment mechanisms 3.

[0033]The position adjustment mechanisms 3 are disposed to the supporting
member 2 at three different positions at equal intervals, i.e., at
intervals of 120 degrees along the circumference of the optical element
1. Although the position adjustment mechanisms 3 are disposed at two
different positions in a fifth exemplary embodiment illustrated in FIG. 6
(described below), the position adjustment mechanisms 3 may be disposed
at three or more positions. For example, the position adjustment
mechanisms 3 may be disposed at four different positions at equal
intervals, i.e., at intervals of 90 degrees.

[0034]The position adjustment mechanisms 3 may be arranged at three or
more different positions not at equal intervals but at different
intervals. If all the position adjustment mechanisms 3 are positioned not
within 180 degrees along the circumference of the optical element 1, the
position adjustment mechanisms 3 can displace the optical element 1
within a positional range defined on a plane of the optical element 1
perpendicularly intersecting the direction of gravitational force.

[0035]Although the position adjustment mechanisms 3 are attached to the
supporting member 2, the position adjustment mechanisms 3 can also be
attached to a member for supporting the supporting member 2. The member
for supporting the supporting member 2 on which the position adjustment
mechanisms 3 are attached may support the supporting member 2 directly or
indirectly via a plurality of supporting members in between.

[0036]The procedure for displacing the optical element 1 relative to the
supporting member 2 by using the position adjustment mechanisms 3 in the
exposure apparatus according to the first exemplary embodiment of FIG. 1
is described below.

[0037]The pressing force of the position adjustment mechanisms 3 against
the optical element 1 is changed by moving the contact positions between
the position adjustment mechanisms 3 and the optical element 1 to
displace the optical element 1 relative to the supporting member 2. More
specifically, as the position adjustment mechanisms 3 press the optical
element 1 toward its central axis in response to an input from a control
unit (not illustrated), the contact positions with the optical element 1
move.

[0038]The input can be a voltage, current, force, heat, or light used as a
command value supplied from the control unit (not illustrated) to move
the contact positions. The input can be selected depending on the
position adjustment mechanisms 3 to be used.

[0039]When an input is given to one position adjustment mechanism 3 not in
contact with the optical element 1 to move the position adjustment
mechanism 3 toward the optical element 1, the position adjustment
mechanism 3 comes in contact with the optical element 1. After the
position adjustment mechanism 3 comes in contact with the optical element
1, if the contact position between the position adjustment mechanism 3
and the optical element 1 is further kept moving toward the optical
element 1, the position adjustment mechanism 3 receives a frictional
force produced between the optical element 1 and the supporting member 2
as a resistance.

[0040]If the contact position between the position adjustment mechanism 3
and the optical element 1 is moved with a force exceeding the frictional
force until the position adjustment mechanism 3 presses the optical
element 1, the optical element 1 is displaced relative to the supporting
member 2 in the direction in which the contact position therebetween has
moved in a plane perpendicularly intersecting the direction of
gravitational force. Other position adjustment mechanisms 3 are retracted
in advance so that the optical element 1 does not come into contact
therewith not to disturb the movement of the optical element 1.

[0041]Upon completion of position adjustment of the optical element 1 in
this way, all the position adjustment mechanisms 3 are made to be not in
contact with the optical element 1. More specifically, after moving the
optical element 1, the contact positions between the position adjustment
mechanisms 3 and the optical element 1 are moved in a direction opposite
to the direction in which the optical element 1 was moved. Thus, the
position adjustment mechanisms 3 are not in contact with the optical
element 1.

[0042]In this way, the force, which is applied to the optical element 1 to
move the optical element 1 while the position adjustment mechanism 3 is
in contact with the optical element 1, is released. Accordingly,
deformation and birefringent of the optical element 1 are also released.

[0043]Before and after the optical performance adjustment of the optical
element 1, there may be a very small change in the force generated
between the optical element 1 and the supporting member 2 by the weight
of the optical element 1. With conventional position adjustment
mechanisms with which the optical element 1 is fixed to the supporting
member 2 using a fixing member, the force applied to the optical element
1 through the fixing member during adjustment causes deformation and
birefringent of the optical element 1.

[0044]In the first exemplary embodiment illustrated in FIG. 1, since there
is no force applied to the optical element 1 through a fixing member,
deformation and birefringent produced due to the adjustment are very
small. Thus, optical performance can be adjusted with high precision.

[0045]With conventional optical element supporting apparatuses with which
external force by adhesive or mechanical fixation is applied to the
optical element 1, if the external force changes by external factors such
as shock and temperature change or creeping of a member, a positional
deviation, deformation, or birefringent of the optical element 1 may
occur.

[0046]In the first exemplary embodiment illustrated in FIG. 1, since
external force for fixation is not applied to the optical element 1, the
force applied to the optical element 1 remains stable over long periods.
Therefore, deformation and a variation in birefringent of the optical
element 1 are very small. Thus, stable optical performance over long
periods can be obtained.

[0047]Thermal actuators having a temperature control unit may be used as
the position adjustment mechanisms 3 of FIG. 1. The thermal actuators may
move contact positions between the thermal actuators and the optical
element 1 by a volume change in the thermal actuators caused by a
temperature change therein.

[0048]When the actuators are 10-mm materials having a linear expansion
coefficient of 10-5 1/K respectively, the actuators change in size
by 100 nm for a temperature change of 1K. Therefore, the use of thermal
actuators having a temperature control unit as the position adjustment
mechanisms 3 can attain both downsizing and high resolution. If
necessary, the use of a material having a low heat expansion (with a
linear expansion coefficient of less than 10-6 1/K) as the
supporting member 2 reduces influence by a volume change due to a
temperature change of the supporting member 2.

[0049]As the position adjustment mechanisms 3 illustrated in FIG. 1,
piezoelectric actuators, pressure actuators, motors, or screws may be
used. However, there may be a case where it is difficult to arrange them
in the vicinity of the optical element 1 and to achieve the required
accuracy when using them as the position adjustment mechanisms 3.

[0050]In that case, like an exposure apparatus according to a second
exemplary embodiment of the present invention illustrated in FIG. 2, the
position adjustment mechanism 3 may be composed of an actuator 3a and a
link mechanism 3b, which changes magnification and direction of
displacement of the actuator 3a. The link mechanism 3b is configured to
come in contact with the optical element 1 and designed to change
magnification and direction of displacement of the actuator 3 as
required.

[0051]If the link mechanism 3b is designed such that the actuator 3a can
be detached from outside of the lens barrel, the actuator 3a can be
replaced if any trouble occurs, thus improving the reliability of the
position adjustment mechanisms 3.

[0052]For the link mechanisms 3b illustrated in FIG. 2, parts having
hinges and joints formed thereon by processing a plurality of notches,
holes, and slots can be used to change magnification and direction of
displacement of the actuators 3a.

[0053]In position adjustment of the optical element 1 illustrated in FIG.
1, when displacing the optical element 1 on the supporting member 2,
frictional force produced between the optical element 1 and the
supporting member 2 serves as a resistance to the position adjustment
mechanisms 3. To reduce the resistance to allow the optical element 1 to
be displaced by a smaller force to improve the accuracy of position
adjustment, it may be useful to reduce the friction coefficient and the
weight of the optical element 1.

[0054]To reduce the friction coefficient, it may be useful to form a
slidable fixing film or apply a liquid film on the contact surfaces
between the optical element 1 and the supporting member 2.

[0055]To reduce the weight of the optical element 1, it may be useful to
apply a force to the optical element 1 in the opposite direction of
gravitational force. Methods for applying a force to the optical element
1 in the opposite direction of gravitational force includes a method for
pulling the optical element 1 in the opposite direction of gravitational
force, a method for supplying a fluid such as a liquid and a gas to apply
a buoyant force and pressure to the optical element 1, and a method for
applying magnetic force to the optical element 1.

[0056]With the method for pulling the optical element 1 in the opposite
direction of gravitational force, wires or coil springs are connected to
the optical element 1 to apply a force thereto to prevent external force
from being applied to any other direction than the opposite direction of
gravitational force.

[0057]With the method for supplying a fluid, a seal structure is provided
to prevent the fluid supplied between the optical element 1 and the
supporting member 2 from flowing in an unwanted direction, and a force is
applied in the opposite direction of gravitational force.

[0058]With the method for applying magnetic force to the optical element
1, a target for receiving magnetic force is attached to the optical
element 1, and a force is applied to the optical element 1 in the
opposite direction of gravitational force via the target.

[0059]Pressure generated by supplying the fluid and magnetic force can
also be used as the position adjustment mechanisms 3 that can displace
the optical element 1 relative to the supporting member 2 without coming
in contact with the optical element 1. This method is used on a premise
that a force by pressure and magnetic force is applied in a direction
perpendicularly intersecting the direction of gravitational force.

[0060]If pulling and pressing forces can be applied by pressure and
magnetic force, a position adjustment mechanism 3 can displace the
optical element 1 in both positive and negative directions. In this case,
the position adjustment mechanisms 3 disposed at least two different
positions can displace the optical element 1 in a plane perpendicularly
intersecting the direction of gravitational force.

[0061]To displace the optical element 1 illustrated in FIG. 1, it is
necessary to determine a moving direction and an amount of movement. It
is also necessary to check whether or not optical performance adjustment
has been made to obtain predetermined conditions. Therefore, the exposure
apparatus according to the present exemplary embodiment includes position
detection units configured to detect an amount of movement of the optical
element 1.

[0062]The position detection units measure aberration of the projection
optical system 83 illustrated in FIG. 8, calculates the amount of
movement of the optical element 1 necessary to settle the aberration
within a tolerance, and displaces the optical element 1 relative to the
supporting member 2.

[0063]More specifically, the position detection units measure aberration
of the projection optical system 83 ready for operation as an assembly
composed of a plurality of optical elements 1. After measuring aberration
of the projection optical system 83 by using the aberration measurement
unit 85, the position detection units displace the optical element 1
relative to the supporting member 2 so that the aberration falls within
the tolerance.

[0064]If aberration is measured after this position adjustment of the
optical element 1 is performed, it is possible to check whether or not
the aberration falls within the tolerance. If the aberration does not
fall within the tolerance, the position detection units displace again
the optical element 1 relative to the supporting member 2. When the
position detection units repetitively perform this aberration measurement
and relative movement of the optical element 1, the aberration can be
settled within the tolerance.

[0065]With the above-mentioned exposure apparatus according to the first
exemplary embodiment, it is necessary to give an input to the position
adjustment mechanisms 3, which displace the optical element 1 to a target
position. However, before performing position adjustment of the optical
element 1 by using the position adjustment mechanism 3 for the first
time, the position of the optical element 1 within a positional range
defined relative to the supporting member 2 is not known.

[0066]Since clearances between the position adjustment mechanisms 3 and
the optical element 1 are not known, the amount of movement of the
optical element 1 in response to the input to the position adjustment
mechanisms 3 cannot be estimated, and nor the amount of change in
aberration accompanying the movement of the optical element 1 can be
estimated. In other words, in the first position adjustment, the value to
be input to the position adjustment mechanisms 3 to settle aberration
within the tolerance is not known.

[0067]Therefore, in aberration measurement and position adjustment of the
optical element 1, the aberration adjustment is repeatedly performed
while estimating an input to be given to the position adjustment
mechanisms 3 based on the input to the position adjustment mechanisms 3
and a result of aberration change in the last adjustment cycle, thus
settling aberration within the tolerance.

[0068]Before position adjustment, although the position of the optical
element 1 within a positional range defined relative to the supporting
member 2 is not known, the optical element 1 must be disposed within an
aberration measurable range.

[0069]The positional range of the optical element 1 is defined relative to
the supporting member 2 in terms of clearances between the position
adjustment mechanisms 3 and the optical element 1. Therefore, the
position adjustment mechanisms 3 may be attached by controlling the
clearances such that the optical element 1 may not be displaced out of
the aberration measurable range even if the optical element 1 is
displaced within the positional range.

[0070]Methods for managing clearances includes a method for using a
clearance adjustment shim, an assembly method with temperature difference
management, an assembly method with pressing force management, a method
for producing a predetermined amount of plastic deformation of members by
using a specified pressing force, and an assembly method with an input
given to the position adjustment mechanisms 3. Any one of these methods
can be used separately, or a plurality thereof can be used in
combination.

[0071]Since the position of the optical element 1 within the positional
range defined relative to the supporting member 2 is not known, it is
also possible to give a predetermined input to the position adjustment
mechanisms 3 before the first aberration measurement in order to specify
a position at which a certain input was given to the position adjustment
mechanisms 3 as an initial position.

[0072]In this case, it is known that aberration measurement has been
performed when the optical element 1 is at a position adjusted by giving
a predetermined input to the position adjustment mechanisms 3. Therefore,
an input to be given to the position adjustment mechanisms 3 satisfying
required moving direction and amount of movement of the optical element 1
can be determined in consideration of an input given to the position
adjustment mechanism 3 before aberration measurement.

[0073]In the case of a projection optical system having undergone the
former aberration adjustment, an input given to the position adjustment
mechanisms 3 in the former adjustment can be utilized. More specifically,
after repeatedly performing the aberration measurement referring to the
previous aberration measurement result, it is useful to record the latest
input given to the position adjustment mechanisms 3 with which the
aberration can be settled within the tolerance, and to give the recorded
input to the position adjustment mechanisms 3 before aberration
measurement for the following measurement.

[0074]An exposure apparatus according to a third exemplary embodiment of
the present invention is described below with reference to FIG. 3. The
exposure apparatus according to the present exemplary embodiment includes
displacement sensors 4 capable of measuring a moving direction and an
amount of movement of the optical element 1.

[0075]The position detection units include a plurality of displacement
sensors 4 capable of measuring at least two axes. Referring to values
output from displacement sensors 4, the position detection units displace
the optical element 1 relative to the supporting member 2 based on the
amount of movement of the optical element 1 necessary to settle the
aberration within the tolerance. The amount of movement is calculated
from a result of the aberration measurement by the projection optical
system 83.

[0076]More specifically, the displacement sensors 4 capable of measuring
displacement of two freedom degrees in a plane perpendicularly
intersecting the direction of gravitational force are disposed at two
different positions on the supporting member 2. When the displacement
sensors 4 are non-contact sensors, a target is attached to the optical
element 1 (measurement target). When the displacement sensors 4 are
optical sensors for detecting a reflected light, a plane facing the
sensors may be provided on the optical element 1, and a reflection film
may be provided on the plane to integrate the target and the optical
element 1.

[0077]In the present exemplary embodiment illustrated in FIG. 3, the
position adjustment of the optical element 1 can be performed referring
to values output from the displacement sensors 4. Therefore, position
adjustment of the optical element 1 can be performed while checking an
actual amount of movement with respect to the amount of movement of the
optical element 1 necessary to settle the aberration within the
tolerance. The amount of movement is calculated from the result of
aberration measurement by the projection optical system.

[0078]In the third exemplary embodiment, the number of measurements of
aberration can be reduced. Accordingly, adjustment of the optical element
1 can be performed in a shorter time than a case without the displacement
sensors 4.

[0079]The displacement sensors 4 in FIG. 3 are provided with an origin
used as a reference for measuring an absolute position of an object under
measurement. When the optical element 1 is displaced, the optical element
1 is returned to the position before displacement by referring to this
origin.

[0080]More specifically, when the displacement sensors 4 are provided with
an origin function, the origin function can be used to return the optical
element 1 to the former position. The origin of the displacement sensors
4 is a reference used by the displacement sensors 4 to measure an
absolute position of an object under measurement. Absolute displacement
of the object under measurement is measured in terms of displacement with
reference to the origin.

[0081]The following describes a case where, after position adjustment of
the optical element 1 has been performed so that the aberration falls
within the tolerance, the position of the optical element 1 relative to
the supporting member 2 is recorded as an origin (reference) and then the
position of the optical element 1 is determined to have been displaced
during transportation and operation.

[0082]In this case, by using the position adjustment mechanisms 3, the
optical element 1 is returned to the position before displacement with
reference to the origin of the displacement sensors 4. When adjustment
for settling aberration within the tolerance is performed again, the
position recorded with reference to the origin is updated to reflect the
latest adjustment result.

[0083]With the method for using the origin of the displacement sensors 4,
when displacement of the optical element 1 arises, the displacement can
be corrected without aberration measurement.

[0084]An exposure apparatus according to a fourth exemplary embodiment is
described below with reference to FIG. 4. The exposure apparatus
according to the present exemplary embodiment is provided with contact
detection units 5 at contact positions respectively between the position
adjustment mechanisms 3 and the optical element 1.

[0085]The exposure apparatus according to the fourth exemplary embodiment
includes the contact detection units 5 such as contact detection sensors
disposed at contact portions respectively between the position adjustment
mechanisms 3 and the optical element 1 and configured to detect the
contacts therebetween. After the contact detection units 5 detect
contacts therebetween, an input given to the position adjustment
mechanism 3 as a command value determines an amount of movement of the
optical element 1.

[0086]Although the contact detection units 5 are disposed on the position
adjustment mechanism 3 at contact positions between the position
adjustment mechanisms 3 and the optical element 1, they may be disposed
on the side of the optical element 1.

[0087]When the contact detection units 5 are pressure sensors, they may be
disposed at other than the contact positions between the contact
detection units 5 and the optical element 1 as long as they can detect
pressure generated when the position adjustment mechanisms 3 press the
optical element 1. Since the contact detection units 5 can detect
contacts between the position adjustment mechanisms 3 and the optical
element 1, the amount of movement of the optical element 1 is determined
from the command value input to the position adjustment mechanisms 3
after the contact.

[0088]With the exposure apparatuses according to the first, second, third,
and fourth exemplary embodiments of the present invention illustrated
respectively in FIGS. 1, 2, 3, and 4 factors such as shock or temperature
change may cause a positional deviation of the optical element 1 relative
to the supporting member 2.

[0089]In this case, a positional deviation is detected by aberration
measurement of the projection optical system or by the position detection
units (the displacement sensors 4), and the position adjustment
mechanisms 3 adjust the position of the optical element 1 so that the
predetermined optical performance is obtained.

[0090]The optical element 1 is adjusted by the position adjustment
mechanisms 3 based on a measurement result by the position detection
units at the time of assembly and adjustment of the exposure apparatus,
installation after transportation, and performance check after starting
operation.

[0091]The performance check after starting operation refers to periodical
performance check and other performance checks performed if a
displacement sensor, an accelerometer, or a thermometer disposed in the
exposure apparatus, for example, included in the projection optical
system 83 detects a change exceeding a specified value. These performance
checks correct degradation in optical performance caused by a positional
deviation of the optical element relative to the supporting member 2,
thus providing stable optical performance over long periods.

[0092]An exposure apparatus according to a fifth exemplary embodiment is
described below with reference to FIGS. 5 and 6. The exposure apparatus
according to the present exemplary embodiment includes two different
contact positions between the position adjustment mechanisms 3 and the
optical element 1. The position adjustment mechanisms 3 displace the
optical element 1 in positive and negative directions along the direction
in which the position adjustment mechanisms 3 move.

[0093]The exposure apparatus includes two different contact positions
between the position adjustment mechanisms 3 and the optical element 1,
and at least two position adjustment mechanisms 3 that can displace the
optical element 1 in positive and negative directions. The contact
positions between the position adjustment mechanisms 3 and the optical
element 1 are moved to press the optical element 1 to displace it
relative to the supporting member 2, thus performing optical performance
adjustment of the optical element 1, and then make all the position
adjustment mechanisms 3 not in contact with the optical element 1.

[0094]The optical element 1 has a concave portion and a position
adjustment mechanism 3 has a convex portion, and vice versa. As the
position adjustment mechanism 3 is displaced in positive direction along
the X axis, the position adjustment mechanism 3 comes in contact with the
optical element 1 at a contact position 6a thereof, and the optical
element 1 is displaced in positive direction of the X axis. On the
contrary, when the position adjustment mechanism 3 is displaced in
negative direction of the X axis, the position adjustment mechanism 3
comes in contact with the optical element 1 at a contact position 6b
thereof, and the optical element 1 is displaced in negative direction of
the X axis.

[0095]Upon completion of position adjustment, an input is given to the
position adjustment mechanism 3 to make both the contact positions 6a and
6b not in contact with the position adjustment mechanism 3.

[0096]The position adjustment mechanism 3 can displace the optical element
1 in both positive and negative directions. Therefore, as illustrated in
FIG. 6, the optical element 1 can be displaced in any directions in a
plane perpendicularly intersecting the direction of gravitational force
by position adjustment mechanisms 3 disposed at two different positions
or more other than opposite positions with respect to the central axis of
the optical element 1.

[0097]To reduce influence of external force when fixing the optical
element 1 or performing position adjustment thereof, fixing members are
not used. Instead, after position adjustment of the optical element 1,
the position detection units make the position adjustment mechanisms 3
not in contact with the optical element 1. However, an exposure apparatus
according to a sixth exemplary embodiment of the present invention
illustrated in FIG. 7 can also sufficiently reduce influence of external
force. The exposure apparatus according to the present exemplary
embodiment includes a coupling member 7 for connecting one position
adjustment mechanism 3 with the optical element 1.

[0098]The contact positions of the position adjustment mechanism 3 formed
between the position adjustment mechanisms 3 and the optical element 1 is
moved to press the optical element 1 to displace it relative to the
supporting member 2, thus performing optical performance adjustment of
the optical element 1, and then make all the position adjustment
mechanisms 3 not in contact with the optical element 1.

[0099]More specifically, when the position adjustment mechanism 3 is moved
in negative direction along the X axis, the optical element 1 is pulled
by the position adjustment mechanism 3 via the coupling member 7, and
accordingly the optical element 1 is displaced in negative direction of
the X axis.

[0100]As the coupling member 7 a wire may be used, which is rigid in the
direction in which the position adjustment mechanism 3 pulls the optical
element 1, but is very weak in at least one direction perpendicularly
intersecting the pulling direction. Upon completion of position
adjustment of the optical element 1 by pulling the optical element 1, the
position adjustment mechanism 3 is moved in positive direction of the X
axis to press the coupling member 7 to bend it. Thus, the force applied
to the optical element 1 is sufficiently reduced.

[0101]Therefore, even if the coupling member 7 is present, which is in
contact with the optical element 1 in the moving direction of the optical
element 1, optical performance adjustment of the optical element 1 can be
performed with high precision, thus providing stable optical performance
over long periods.

[0102]By using an exposure apparatuses according to any one of the
above-mentioned exemplary embodiments, a device (a semiconductor
integrated circuit element, a liquid crystal display element, etc.) is
formed and manufactured through a process of exposing a substrate (a
wafer, a glass plate, etc.) on which sensitive agent is applied, and a
process of developing the exposed substrate. A process for processing the
developed substrate includes etching, resist separation, dicing, bonding,
and packaging.

[0103]While the present invention has been described with reference to
exemplary embodiments, it is to be understood that the invention is not
limited to the disclosed exemplary embodiments. The scope of the
following claims is to be accorded the broadest interpretation so as to
encompass all modifications, equivalent structures, and functions.